Abstract
Objective The purpose of this study was to compare the load at failure and mode of failure
of four constructs used to stabilize a tibial tuberosity osteotomy, including two
vertically aligned pins (V), two horizontally aligned pins (H), two vertically aligned
pins with a tension band wire (V-TB) and two horizontally aligned pins with a tension
band wire (H-TB).
Study Design Eighteen pairs of cadaveric tibiae were randomized to receive a TB or no TB. One
limb was randomized to be in the H or V group. The contralateral limb was then assigned
to the opposite configuration. One pair of limbs was used as a control. A tensile
force was applied to the patellar ligament until construct failure.
Results There was no significant difference between the mean load at failure of the H (595 N)
and V (556 N) groups or between H-TB (1032 N) and V-TB groups (1034 N) (p = 0.487 and p = 0.238, respectively). The TB constructs were significantly stronger than the pin
only constructs (p < 0.001). The mode of failure was similar for the pin only constructs, regardless
of pin orientation. The TB constructs and control tibias failed at similar loads,
most commonly by patellar ligament rupture.
Conclusion The use of vertically aligned pins versus horizontally aligned pins does not affect
construct strength. These results support the placement of pins in a vertically or
horizontally aligned fashion. When performing a tibial tuberosity osteotomy, the addition
of a TB adds significant strength to the construct.
Keywords
tibial tuberosity transposition - patellar luxation - mechanical testing - tension
band wire - dog
